The diagonal of a square is equal to the side of an equilateral triangle. If the area of the square is 15?3 sq cm, what is the area of the equilateral triangle?
4. The co-ordinates of the centroid of a triangle ABC are (-1 , 4). What are the co-ordinates of vertex C if co-ordinates of A and B are (-3 , -1) and (3 , 5) respectively?
10. In ?PQR, S and T are points on side PQ and PR respectively. ST is parallel to QR. If lengths of PS, SQ and PR are 6 cm, 9 cm and 12.5 cm respectively, what is the length of TR?